Recently, the use of UASs in connection with entertainment and displays has been suggested. For example, in US Publication Nos. US2014/0236388; US2014/0231590 and US2014/0123099, it is suggested that a number of untethered UASs with lights flying in formation may provide an array of “flixels.” This same applicant suggests using untethered UASs to carry character figures in the sky and moving the UASs to make it appear that the figures are moving like marionettes. Alternative uses for untethered UASs as part of a display have also been suggested.
In all these suggested uses, however, the UAS has a power supply onboard to achieve flight, presumably a battery of significant weight. And in these suggested uses, the UAS would additionally be required to carry a payload. For example, a lamp and its power source carried aloft by a UAS must be sufficiently large and/or powerful if the lamp is to be visible while high off the ground, and to overcome area light pollution. The same holds true for size and visibility if the UAS is to lift a flying marionette.
In view of the foregoing, it would appear that the UASs contemplated by the foregoing would be large and powerful enough to keep their payload aloft, and potentially exceed five pounds in weight. However, regulations may impose weight restrictions on untethered UASs used for commercial purposes, such as display and entertainment to paying customers. Accordingly, there exists a need for a tethered UAS that may be legally used for commercial purposes. There also exists a need for a tethered UAS that may avoid the need to carry significant weight aloft.
Some UASs which are tethered to a base, such as a military vehicle, have been disclosed in the literature. However, these UASs have typically been used in military or data acquisition purposes, and have not been used in displays such as water and light displays, and thus do not address how a UAS may be used in a display application.
Where non-tethered UASs have been suggested for use with displays as noted above, other issues arise. For example, such non-tethered UASs are typically controlled by radio signals. However, such radio signals may be interrupted by nearby radio transmissions, may malfunction, or may otherwise send erroneous commands. Worse yet, malevolent third parties may intentionally interfere with the radio transmissions to control the UASs. Accordingly, there exists a need for a UAS that may be controlled with a reliable source of control signals to control the UAS's flight and other actions.
Another issue is that non-tethered UASs have the potential to fly off and injure persons observing the display or elsewhere. This may occur where the above-referenced interference occurs, or where some other mis-programming, erroneous control commands, or other malfunction occurs. Accordingly, there is a need for a UAS that is prevented from flying off its intended or desired path and/or injuring someone.
In certain situations, nets may be used in public demonstrations involving UASs to protect viewers in the event a UAS flies toward the crowd. However, such a net would not be suitable for a large water display, such as where fountains are located in a several acre reservoir, due to their enormity, the challenges of managing large nets in windy conditions, and the undesirable effect of visual interference for spectators.
As noted above, where a UAS is not tethered to the ground, it will typically include a battery with a limited duty cycle and lifespan as its power source. When the battery power begins to degrade, the UAS may behave erratically or be unable to stay aloft. This effect may be acceleration where the UAS carries high-power lighting, marionettes or other items that may be heavy and rapidly deplete battery power. Accordingly, there is a need for a UAS that may stay aloft for extended periods even when supporting heavy payloads. Additionally, there is a need for a UAS which carries a battery, as a standby power source in the event of a disruption of power from its tethered ground source.